Many different types of containers are used for transporting and displaying goods. Plastic collapsible bins with foldable side panels are in common use. An example of a collapsible bin is shown in U.S. Pat. No. 4,674,647 to Gyenge et al.
Plastic collapsible bins can vary in size to accommodate the intended items or materials with which they will be used. Larger bins can be handled by standard forklifts to facilitate transport and storage. The bins are typically made of a base with hinged side and end panels. The base and the side and end panels are made of an injection molded plastic. The panels include hinges, often integrally formed, at their bottom edges. The hinges cooperate with the base to allow the end and side panels to be folded downward over the base when the bin is not in use. To erect the side and end panels, the panels are typically extended upward from their folded position and interlocked at their edges. To accommodate the interlocking, the edges of the side and end panels include mating or interlocking members. The side and end panels are latched to each other when in the fully erected position for stability.
A commonly occurring problem with collapsible bins in current use results from the base warping over time such that the sides of the base tend to bow outward. The outward bowing of the base prevents the mating members at the edges of the panels from properly aligning and interlocking. This can occur, for example, when bins are stacked upon each other, thereby causing outward pressure due to weight on the side panels. Another potential cause of outward bowing is improper latching of the panels, which causes the panels to lean outward when placed under load. Repeated loading and use in hot temperatures further contributes to the outward bowing.
The present invention provides a collapsible bin with an improved side and end panel interlocking mechanism to overcome the effect of outward bowing of its base and panels.